Lost 3 rolls during development - WTF

I had 3 rolls of color neg that I needed to develop, 1 roil of Portra 400 in 120, and some Fujicolor and Kodak gold in 35mm. I managed to fit it all in one tank with some luck. As usual I heated up my chemicals (Tentenal press kit) in my water bath and once it hit 102 degrees I started to develop. Nothing out of ordinary, but I did notice that the dev was a bit dark.

Once I was in the wash stage I took a peek and noticed that the film was completely blank. it had the orange mask, but no photos, no edge markings, nothing. Kind of wondering exactly what happened. I mixed the kit in mid feb, and last used it in mid March and it was perfect. I keep track of what I develop and this kit only had 3 rolls of 120 and 7 sheets of 4x5, still plenty under the limit.

Did I wait too long to develop this film, were the chemicals out of date from the time I mixed them?

That sounds more like getting your dev and blix mixed up. I've been using C41 chems for over a year so a few months is nothing. No edge marking, means no development took place at all. Mixing up chems is the most likely cause especially if you noticed the colour of the developer was odd.

If the BLIX would have been bad, you'd have gotten weird colors, but definitely an image. So unless you really mixed up CD and BLIX, I'd say your CD went bad. You can test it like B&W developer with a small test clip of B&W film.

Was your developer stored in an oxygen-free (i.e. glass or PETE bottle under butane or with air removed) and in the fridge? If not, it was probably dead. Stored properly, it should have been fine - I've tested 4 months and found no change, but it will die in a few days if left with oxygen.

An "odd" colour to the dev implies that maybe you put bleach in instead, or maybe you accidentally dumped some blix into your developer on the previous session. It also goes a bit darker from oxidation but it's harder to tell the difference between tea-colouring from oxidation and tea-colouring due to running a bunch of rolls through it and having some of the sensitisation dyes wash out.